Re: [PATCH 11/43] xfs: reduce metafile reservations

Darrick J. Wong
2025-02-07T04:26:04Z

On Fri, Feb 07, 2025 at 05:19:31AM +0100, Christoph Hellwig wrote:
> On Thu, Feb 06, 2025 at 12:52:49PM -0800, Darrick J. Wong wrote:
> > On Thu, Feb 06, 2025 at 07:44:27AM +0100, Christoph Hellwig wrote:
> > > There is no point in reserving more space than actually available
> > > on the data device for the worst case scenario that is unlikely to
> > > happen. Reserve at most 1/4th of the data device blocks, which is
> > > still a heuristic.
> >
> > I wonder if this should be a bugfix for 6.14? Since one could format a
> > filesystem with a 1T data volume and a 200T rt volume and immediately be
> > out of space on the data volume.
>
> Yeah. But for this to be safe I think we also need the previous patch
> to sitch to the global reservations. Which at least in the current
> form sits on top of the freecounter refactoring..

<nod> Well at the moment we're safe against that scenario because mkfs
will blow up and not complete the format. :D

--D